By-pass valve



May l, 1945.

BY- PASS VALVE Filed May 4, 1944 72 69 K 7a 7a 70 77 7 Eg-.1.

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Patented May 1, 1.945

'hompson Products, Inc., a corporation of hio AApplication May 4,1944,1sena1 No. 534,062

5 claims. j (ci. zw-45t This invention, relates to a by-pass valve particularly adapted for use in a relief and oy-pass valve assembly in pumps'such as those used Vfor the transfer of fuel in aircraft.

The present invention constitutesan' improvement over the by-pass valve constructionxde scribed in my copending application Serial No.

512,891, led December.4, 1943. In that application I have Vshown a nested assembly of elements constituting both, 'a relief valve and `a by-pass valve in a fuel pump for aircraft, Y

According to the :present invention, the by-pss Lvalve is so constructed as to be much more economical of manufacture 'and more eillcient in' operation. The by-pass valve is formed in two parts, one of which can be simply and economically made by a die-casting operation, and th'e other of which is a simple form of stamped metal member. It is therefore an importantobject of vthis invention to provide a by-pass valve construction of an improved, simple and cheap construction that is efficient in-operatin,

Other and further important objects of this invention will be apparent from the disclosures in the speciiicationand the accompanying drawn the drawing:

Figure lis a longitudinal sectional view of a fuel transfer pump with which a relief and bypass valve assembly is illustrated;

Figure `2 is an enlarged sectional, exploded view of the reliefand by-pass valve assembly showing the construction of my improved 'DY-pass valve;

Figure 3 is a sectional view o f'the relief and by-pass valve assembly in nested relationship; and Figure 4 is a top plan view ofthe washer element of the by-pass valve.

The reference numeral I0 (Fig, 1) indicates generally an aircraft fuel pump with which`a relief and by-pass valve assembly, indicated generally by the reference numeral 33, is ,adapted to be associated. Said pump I0 -cornprisesa lpump casing Il, a valve housing ,I2 mounted thereon,

and a valve housing cover I3 ,secured to said housing I2 and tothe pump casing II by means of bolts and nuts I4. The pump here illustrated 50 with an upwardly dished central portion 44 for is of the rotary vane type, the bore of the pump casing Il being vprovided withra pump liner I5 within which a-rotor I6 is adapted to be driven'. 'Ihe pump casing II is provided with an intake I1. and an outlet `l8 for connecting the pump in a fuel line to an engine, or other point to which )outlet sldecf whichis formed a port 2 5 which areA in valve controlled now co tion with interior portion 30 ofthe valve hous-` fuel is to be delivered. Internally, the pump cas#- ing is divided by a' partition Illa, 'on the intake side ofwhich is formed'a port I9, and n the [l-goth of j nica-A Aing I2. J

Said valve housing I2 is formed with an 4axially concentric, annular partition'2l`, which may-be 10 integrally cast with the valve housing I2.f Said partition 2I providesone'or more ports 25 in -communication with the port I9 and the intake- I1. 0n the outlet side of vsaid annular partition 2 I, the-partition is cut away, as at 2-6, to provide l5 flow communication 4from the outlet port k20 to.

the interior of the annular partition 2l. The inner upper edge of saidpartitionZI lprovides a relief valve seat 23 the full circumference of which is completed by'a horizontally extending integral portion 23 lof the valve housing I2.

Within said partition 2 I is formed an open cylin-V drical well 3| of reduced diameter for receiving the lower portion ofthe relief'valve 34. A gasket 32, having openings conforming with the ports 25 I9 and x2li, is suitably, positioned between the pump casing I l and the valve housing I2 for nproviding a tight joint therebetween. The lower annular edge of the partition 2 I rests directly upon said gasket a2, which is clamped between said lower edge and the partion I,3aof the pump housing.

The reliefand by-pass valve assembly 33 (Figs. l I

2 and `3) is adapted to be assembled-in nested relationship within the valve housing I2. Said- 35 assembly comprises a relief valve 34, suitably i formed of a metal stamping withan upper, outturned cylindrical flange 35 in sliding contact with-the cylindrical bore 36 formed in the upper portion of saidvalve housing I2, and with a lower 40 closed bottom portion-31 having an upstanding cylindrical side wall 38v slidablewithin the well 3I. Said relief valve 34 is further formed with an intermediate offset-portion 39, provided on its outer surface with a beveled seating face 40, and

on its inner surface with a flattened shoulder '4'I.

Above the offset portion`39,,the side' wall'of the relief valve 34`is` provided with .ports 42, while ports 43 are formedin the lower side wall. The bottom wall 31 of said relief valve is provided the purpose of centering a'coiled` spring 45,

"adapted ,to rest thereom` Thelower side wall of said relief valve 3 4lis provided with inwardly ahy-pass valve disk 41, as will later be explained in greater detail. Y 'The by-pass valve disk 41 is formed with an upper disk-like portion presenting an outer periphery 48 for sliding engagement with said ribs 46, and with a lower dependent annular flange 49 for partially enclosing and confining the upper end of said coiled spring 45. The 'oy-pass valve disk 41 is also provided, on its upper face, with a raised, flat annular surface 50 which constitutes the seating surface of the disk, as will later be explained.

A by-pass valve 5l formed intwo parts and comprising a lower member 5Ia and an upper Washer 5Ib, is adapted to be nested within the relief valve 34 to provide a seat for the by-pass disk 41. Said member 5Ia is formed with a dependent annular flange 52 having an outside diameter equal to the diameter of the circle defined by the inwardly extending ribs 46. The

lower surface of said flange 52 provides .a plane annular face 53 against whichrsaid by-pass valve disk 41 is adapted to be urged by the spring 45. Above said dependent annular flange 52, the bypass valve 5I is provided with an annular shoulder 54, the bottom face 55 of which is plane and adapted to rest upon and b e supported by the 51 to the interior ofsaid relief valve 5I above the by-pass disk 41. The washer SIb is adapted .to rest upon and be centered on the tops 51a of said pillars 51, and for this purpose the washer 51h is provided. with an inner, downwardly extending ange 5Ic that fits over the inner edges of said pillars 51.

When the rotor I6 is not operating and it is necessary to by-pass iluid around said rotor, the fuel can be caused to flow under pressure, as by means of an emergency hand pump (not shown), up through the port I9, through the corresponding port 25 in the valve housing I2, through the ports 42 in the relief valve 34 and through the ports or spaces between the pillars 51 of the by pass valve 5I to act against the by-pass disk41. Since the spring 45"*is relatively very light, being merely suilcient to hold the by-pass disk 41 against its seat whenl the iluid pressure above and below the by-pass disk is substantially the same, said by-pass disk 41 is depressed under the conditions assumed to permit the fuel to continue in its ow through the opening thereby provided and out through the ports 43, 26 and 20 to theoutlet side I8 of the pumpcasing.

In the operation-of the by-pass disk 41, there is no tendency of the disk to become cocked and stuck, since the'outer peripheral surface 46 is rounded (Fig: 2) to give the eilect of a thin circular disk rather than that of a, piston. Fur'- thermore, the coiled spring 45 acts upwardly against the under side of said. disk with a preslure that is uniformly distributed about its com-- plete circumference and adjacent its outer periphery. The spring 45 is itself centered by the opstanding central portion 44 in thel closed bottom 31 of the relief valve 34, and its top winding is confined within the dependent iiange 49 ofv said by-pass disk 41, so that the spring cannot easily be displaced. In addition, the amount by which the spring 45 can be compressed is limited by the lower dependent flange 49 of the by-pass disk 41 striking against the closed bottom wall 31 of the relief valve 34, so that the spring 25 can never be compressed beyond its elastic limits.

As a matter of fact, the movement of the bypass disk 41 is very slight in actual practice, since the opening'that is uncovered is of such large diameter as to permit substantially unobstructed flow of the fuel upon sligft'depression of the by-pass disk.

Between the valve housing cover I3 and the valve housing I2, a diaphragm 58 is clamped about its periphery by the same bolts I4 that hold the pump casing I I, valve housing I 2 and cover I3 together. With the relief valve 34 properly seated, the upper face 59 of the washer 5Ib forming part of the by-pass valve 5I is in touching contact with said diaphragm58.

A stamped washer 60 is positioned above said diaphragm 58 to rest thereagainst with its downwardly offset peripheral portion 6I opposing the upper annular surface 59 of said by-pass valve washer 5Ib. Said disk 60 is further formed with a semi-spherical, centrally depressed portion 62 for receiving a ball 63. A second stamped metal disk 64 is formed with a, complementary semispherical portion 65 -which rests against said ball 63 to be centered thereby. Said disk 64 is also provided with a downwardly offset peripheral portion 66 which forms a seat. for the bottom turn of a regulating spring 61 for adjusting the pressure against said diaphragm 56.

'I'he regulating mechanism includes a screw 68, which is adapted to extend through anopening 69, in the top of said cover I3. Said screw 66 is provided with an integral flange 19, between which and the underside of the cover I3 is positioned a gasket 12. A check-nut 13 serves to draw the flange and gasket tightly up against the under surface of the top wall of the cover I3 to provide a fluid-proof seal. A flanged disk 14 is operatively threaded upon the lower end of said screw 68 and isv provided with air-offset peripheral flange 15 for bearing against the upper end of the coiled spring 61. For the purpose of guiding said disk 14, a plurality of longitudinally extending integral ribs 16 are formed on the inside of the side wall of said cover I3, and the peripheral'ange 15 of said disk 14 is slotted as at 11 for sliding engagement with said ribs. The screw 66 is further provided'with a screw-driver slot 18, by means of which the desired adjustment can be made from the outside, without removing the cover I3 or any accessory thereto.

To accomplish the adjustment of the regulating spring 61, and thereby regulate the amount of pressureV exerted downwardly against the dia-y phragm 56, it is merely necessary to loosen the vcheck nut 13 and turnvthe screw'l 66 in the de.

s'ired direction.' By virtue of theA threaded engagement between the disk 14 and the threaded portion of the screw 68, said disk 14 will be moved upwardly or downwardly to lessen or increase the compression force of the spring 61. The slidable engagement between the ribs 16 of the cover I3 andjtneslotted periphery 11 of the disk 1'4` prevents said disk from turning and insures a positive downward pressure against the spring 61.

Furthermore, any tendency of one end oi the4 spring 61 to b e deflected from the horizontal due appended claims.

to movement of the disk 14' is neutralized by reason Vof the free mobility of the d isk 64 about the ball 63. A As a result, only the axial component of the'tensio'n of the spring is transmitted, without any7 interfering factors, through the disk tft, the ball 63 and the disk 6U to the diaphragm 58. The downward pressure on the diaphragm s further transmitted through the by-pass valve l to the' relief valve 3&through the gasket 56,

whereby the relief valve lis held against its seat il with the desired pressure.

In case the pressure tends to build up'beyondthat for which the relief valve'ls set, the fluid pressure acting upwardly against the offset portion 3d of said relief valve 36 and against the under side of the bi1-pass dis-km win tend to lift the relief valve 3d off of its seat n28, and fluid will pass into the cavity @d and through the ports 42 and iii into the port i@ on the intake side of the pump. Fluid also passes through the port i3 in the lower portion of the relief valve 34 and out through the opening provided when the seat 28 is uncovered. Since the opening provided when the valve :it is lifted on of its seat 28 is of relatively large diameter, the valve need be lifted .Y only slightly to provide for the ilow of a considerable volume of the fuel from thev outlet to the intake side of the pump.

nesting inside said reliefvalve to seat against said annular shoulder and having` circumferenan annular washer adapted to be mounted on the y tops of said pillars and having an inner. downwardly turned circular flange for centering said washer upon said pillars, said washer transmitting forces from the diaphragm to said lay-pass valve to effect a seating thereof under the desired pressure. j

3. In a diaphragm type relief and by-pass valve assembly, a `hir-pass valve comprising a ring-like member having a lower annular seating surface and peripherally spaced upstanding pillars affording fluid iiow ports therebetween, a relief valve member having a shoulder against which Returning to the by-pass valve 5|, the lower valve element 5 la can be simply forned ina die-` casting operation out of aluminum or other light metals or alloys. For 'ease of die-casting, the pillars 51 are given a vtapered form. The washer 5t is formed by a simple stamping operation from a metal ring or annulus. This construction is much simpler and less costly of manufacture than `the integral, one-piece by-pass valve Villustrated in my pending application Serial No. 512,891.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from'l the principles of this invention and it is, therefore, not

the purpose to limit the patent granted thereon otherwise than necessitated by the scope of the What-I claim is:

l. A relief and b'y-pass valve assembly, comprising a relief valve member, having a closed bottom, an annular :shoulderl and a ribbed cylindii-ical wall provided with ports, a by-pass valve said annular seating surface is adapted to be seated, and an annular washer adapted to be mounted on the tops of said pillars and having an inner downwardly turned circular ilange for centering said washer upon said pillars, said washer transmitting` forces from the diaphragm Sto said by-pass valve to effect a seating thereof against said shoulder under the desired pressure.

4. A lay-pass valve comprising a die-cast ringlikemember having a lower annular seating surface and a plurality of peripherally spaced upn standing pillars. and an annular washer having an inner downwardly turned ilange for centering said washer on top of said pillars.

5. Aby-pass valve comprising a die-cast ring*- like member having a pair of axially spaced lower annular seating surfaces and a plurality of peripherally spaced upstanding pillars, and an aannular ,washer having an inner `downwardly turned flange for centering said washer on top of said pillars. l

MICHELE CASERTA. 

